inspec/www/source/javascripts/stars.js
Hannah Maddy bd4a73cfb9 WIP New Inspec.io
Base SCSS, JS, fonts, images, HTML ported over to old inspec.io
tempting engine.
—To do:
Media queries, Header, footer, docs, tutorials
2017-01-20 10:22:51 +01:00

90 lines
2.9 KiB
JavaScript

var WIDTH = window.innerWidth,
HEIGHT = window.innerHeight,
MAX_PARTICLES = 100,
DRAW_INTERVAL = 20,
container = document.querySelector('#container'),
canvas = document.querySelector('#pixie'),
context = canvas.getContext('2d'),
gradient = null,
pixies = new Array();
function setDimensions(e) {
WIDTH = window.innerWidth;
container.style.width = WIDTH+'px';
canvas.width = WIDTH;
canvas.height = HEIGHT;
}
setDimensions();
window.addEventListener('resize', setDimensions);
function Circle() {
this.settings = {ttl:8000, xmax:5, ymax:2, rmax:10, rt:1, xdef:960, ydef:540, xdrift:4, ydrift: 4, random:true, blink:true};
this.reset = function() {
this.x = (this.settings.random ? WIDTH*Math.random() : this.settings.xdef);
this.y = (this.settings.random ? HEIGHT*Math.random() : this.settings.ydef);
this.r = ((this.settings.rmax-1)*Math.random()) + 1;
this.dx = (Math.random()*this.settings.xmax) * (Math.random() < .5 ? -1 : 1);
this.dy = (Math.random()*this.settings.ymax) * (Math.random() < .5 ? -1 : 1);
this.hl = (this.settings.ttl/DRAW_INTERVAL)*(this.r/this.settings.rmax);
this.rt = Math.random()*this.hl;
this.settings.rt = Math.random()+1;
this.stop = Math.random()*.2+.4;
this.settings.xdrift *= Math.random() * (Math.random() < .5 ? -1 : 1);
this.settings.ydrift *= Math.random() * (Math.random() < .5 ? -1 : 1);
}
this.fade = function() {
this.rt += this.settings.rt;
}
this.draw = function() {
if(this.settings.blink && (this.rt <= 0 || this.rt >= this.hl)) {
this.settings.rt = this.settings.rt*-1;
} else if(this.rt >= this.hl) {
this.reset();
}
var newo = 1-(this.rt/this.hl);
context.beginPath();
context.arc(this.x, this.y, this.r, 0, Math.PI*2, true);
context.closePath();
var cr = this.r*newo;
gradient = context.createRadialGradient(this.x, this.y, 0, this.x, this.y, (cr <= 0 ? 1 : cr));
gradient.addColorStop(0.0, 'rgba(255,255,255,'+newo+')');
gradient.addColorStop(this.stop, 'rgba(255,255,255,'+(newo*.6)+')');
gradient.addColorStop(1.0, 'rgba(77,101,181,0)');
context.fillStyle = gradient;
context.fill();
}
this.move = function() {
this.x += (this.rt/this.hl)*this.dx;
this.y += (this.rt/this.hl)*this.dy;
if(this.x > WIDTH || this.x < 0) this.dx *= -1;
if(this.y > HEIGHT || this.y < 0) this.dy *= -1;
}
this.getX = function() { return this.x; }
this.getY = function() { return this.y; }
}
for (var i = 0; i < MAX_PARTICLES; i++) {
pixies.push(new Circle());
pixies[i].reset();
}
function draw() {
context.clearRect(0, 0, WIDTH, HEIGHT);
for(var i = 0; i < pixies.length; i++) {
pixies[i].fade();
pixies[i].move();
pixies[i].draw();
}
}
setInterval(draw, DRAW_INTERVAL);